If you doubled everyone's salary, the gain would almost certainly be absorbed by real estate or some other necessity.
Regulations on maximum working hours, access to fair housing, education, healthcare etc might work better.
Providers of necessities can demand large portions of people’s income due to lack of supply. It’s a basic monopoly. We see that in real estate, health care, education, elderly and child care.
They can’t charge endlessly because at some point people are priced out. Homelessness, lack of education, delaying medical care until an emergency and relying on laws that non-payers cannot be denied treatment.
But they can travel up the supply demand curve and take from everybody that can still afford it, because the supply is constrained. TVs are cheap, because of competition from overseas. Land or health care prices are not.
What do you think would be the best way to help ensure everyone gets a fair share?